macro expansion issue

Author: Kivooeo

compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs

@@ -1553,17 +1553,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             {
                 ("(".to_string(), call_span.shrink_to_hi().to(error_span.shrink_to_hi()))
             } else {
-                (
-                    format!(
-                        "{}(",
-                        source_map.span_to_snippet(full_call_span).unwrap_or_else(|_| {
-                            fn_def_id.map_or("".to_string(), |fn_def_id| {
-                                tcx.item_name(fn_def_id).to_string()
-                            })
-                        })
-                    ),
-                    error_span,
-                )
+                let snippet = source_map.span_to_snippet(full_call_span).unwrap_or_default();
+                let method_name = if snippet.contains("::") {
+                    snippet.rsplit("::").next().unwrap_or(&snippet).to_string()
+                } else {
+                    snippet
+                };
+                (format!("{}(", method_name), error_span)
             };
             let mut needs_comma = false;
             for (expected_idx, provided_idx) in matched_inputs.iter_enumerated() {

tests/ui/not-enough-arguments.rs

@@ -23,6 +23,22 @@ fn bar(
     println!("{}", f);
 }
 
+macro_rules! delegate {
+  ($method:ident) => {
+      <Self>::$method(8)
+      //~^ ERROR function takes 2 arguments but 1
+  };
+}
+
+struct Bar;
+
+impl Bar {
+  fn foo(a: u8, b: u8) {}
+  fn bar() {
+      delegate!(foo);
+  }
+}
+
 fn main() {
   foo(1, 2, 3);
   //~^ ERROR function takes 4 arguments but 3

tests/ui/not-enough-arguments.stderr

@@ -1,5 +1,25 @@
+error[E0061]: this function takes 2 arguments but 1 argument was supplied
+  --> $DIR/not-enough-arguments.rs:28:7
+   |
+LL |       <Self>::$method(8)
+   |       ^^^^^^^^^^^^^^^--- argument #2 of type `u8` is missing
+...
+LL |       delegate!(foo);
+   |       -------------- in this macro invocation
+   |
+note: associated function defined here
+  --> $DIR/not-enough-arguments.rs:36:6
+   |
+LL |   fn foo(a: u8, b: u8) {}
+   |      ^^^        -----
+   = note: this error originates in the macro `delegate` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: provide the argument
+   |
+LL |       <Self>::$method(8, /* u8 */)
+   |                        ++++++++++
+
 error[E0061]: this function takes 4 arguments but 3 arguments were supplied
-  --> $DIR/not-enough-arguments.rs:27:3
+  --> $DIR/not-enough-arguments.rs:43:3
    |
 LL |   foo(1, 2, 3);
    |   ^^^--------- argument #4 of type `isize` is missing
@@ -15,7 +35,7 @@ LL |   foo(1, 2, 3, /* isize */);
    |              +++++++++++++
 
 error[E0061]: this function takes 6 arguments but 3 arguments were supplied
-  --> $DIR/not-enough-arguments.rs:29:3
+  --> $DIR/not-enough-arguments.rs:45:3
    |
 LL |   bar(1, 2, 3);
    |   ^^^--------- three arguments of type `i32`, `i32`, and `i32` are missing
@@ -37,6 +57,6 @@ help: provide the arguments
 LL |   bar(1, 2, 3, /* i32 */, /* i32 */, /* i32 */);
    |              +++++++++++++++++++++++++++++++++
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0061`.